the jetties layer, finally we saw the thicker limestone on the N.E. side of Zenis not far away from our Tetrapod locality. Here the eng. was at least ten feet thick and at the top a mass of closely compacted angular or rather sub- rounded pieces mixing of several varieties of limestone but also boulders of a hummock thin bedded shale dorworth grey, small & quartzite with desert like rounded sandps and a classic craize sandstone. These latter pieces can have come from the jetties, but saw none of the underlying Laurentian igneous granite-gneiss. At the base the boulders all above layer some two feet long, and at times we met thick and run a four layer. All of these pieces had the corners rounded but none could have been transported far. It would therefore seem as if during the deposition of the Zenis the sea floor had been folded with parts rising into subaerial ridges. It was then these ridges that furnished the boulders of therelies as harder beds to make up the limestone.